This invention relates to tufting machines and tufted fabrics and more particularly to a method and apparatus for forming a new fabric having in alternate rows of stitching selective cut pile and loop pile wherein the cut pile in alternate rows are of different pile height and all the loop pile is of a third and lower pile height.
In the art of tufting, a plurality of yarn carrying needles are reciprocably driven through a backing fabric fed through the machine to form loops which are seized by respective oscillating loopers or hooks on the opposite side of the backing. The loopers may point in the direction of feed of the backing and the seized loops shed on the return movement of the loopers to form a loop pile, or the loopers may point in the direction opposite to the direction in which the fabric is being fed, and cooperate with respective oscillating knives to cut the loops at the closed end of the looper to form cut pile. A major advance in the tufting art occurred when, as disclosed in U.S. Pat. Nos. 2,876,441 and 2,966,866, a pattern attachment which fed yarn to the needles at two different speeds selectively was added to a loop pile tufting machine. The slower speed was such that the yarn fed thereby could not accommodate the yarn requirements of the needles. The needle thus drew back or robbed back yarn from the preceding stitch to form a loop. This allowed production of patterns having high loops and low loops, the low loops being created by the backrobbing process.
The next major advance occurred when, as disclosed in U.S. Pat. No. 3,084,645, a spring clip was added to a looper pointing in the direction in which a cut pile looper points, i.e., opposite the direction of fabric feed, and used in combination with a backrobbing yarn feed pattern attachment. The looper acted together with a knife and when sufficient yarn was fed to the needles the loop remained on the looper and moved toward the closed end to be cut by the knife. However, when the amount of yarn fed was insufficient, the needle pulled yarn from the preceding loop to force the spring clip away from the looper and allowed the loop to slip off. This gave the stylist the ability to produce high cut pile and low loop pile selectively in the same row of stitching, i.e., by the same needle.
Many advances have occurred in the tufting art since that time. Additional patterning effects have been created by laterally shifting the needles in steps according to a pattern prior to insertion into the backing which, when using different yarns threaded through alternate needles, can produce various patterning affects. In U.S. Pat. No. 3,908,570 two needle bars are independently shifted laterally in this manner. Two different levels of cut pile fabric has been patterned using the mechanism disclosed in U.S. Pat. No. 3,138,126 and three level cut pile has been produced by the mechanism disclosed in U.S. Pat. No. 3,075,482. U.S. Pat. No. 3,919.953 discloses means for producing alternate rows of even level cut pile and loop pile, and U.S. Pat. No. 4,134,347 discloses apparatus and means for producing loop pile and cut pile in the same row of substantially the same pile height. From this it should be apparent that the broadloom carpet stylist is constantly seeking new patterning ability and that great effort is exerted in the industry toward this end.